Thread repair inserts are well known in the art. Such an insert can comprise a sleeve having threaded interior and exterior surfaces or a helical coil. For an example of the sleeve-type inserts, see the thin wall and spark plug series TAP-LOK (registered trademark) Inserts manufactured and distributed by Groov-Pin Corporation, 1125 Hendricks Causeway, Ridgefield N.J.
The insert is used to repair a threaded hole after the threads have been stripped away. Typically, the stripped hole is "drilled out" using a drill bit having a slightly larger diameter than the diameter of the original threaded hole. This completely removes the stripped threads. The insert must then be coaxially aligned with the hole. Great care must be taken when aligning the insert with the hole. If the insert is not perfectly aligned with the hole; the repair will be imperfect and must be redone. Of course, this makes the use of inserts difficult and expensive because alignment of the insert is not easily accomplished. To date, no insert has been developed which easily overcomes the alignment problem.